Cancer or neoplasm is the malignant new growth anywhere and elsewhere in the body system. It is characterized by unregulated proliferation of cells and a growing public health problem whose estimated worldwide new incidence is about six million cases per year. In most of the countries, cancer is second only to heart disease as cause of death. It can arise in any organ of the body but some sites are prone to attack than others such as breast, throat, intestine, leukocytes etc. Each cancer is propagated from a single cell that cut at some stage, it becomes free from its territorial restraints, which form a family of cells that multiply without limits and appear in the form of tumors.
During the transition from normal cell to a tumor cell a profound and heritable change occurs which allows a tumor cell to determine its own activities largely irrespective of the laws that govern so precisely the growth of all normal cells in an organism. This newly acquired property, which is known as autonomy, is the most important single characteristic of tumor cells since without it there would be no tumors. Another distinguishing characteristic of tumor cells is their lack of perfect form of function. The differences that exist between cancer and normal cells are that, compared to normal cells, cancer cells have a) low pH b) greater free radical character c) tumor produced hormone peptides d) tumor associated antigens e) lower calcium ion and higher potassium ion concentration f) different potassium isotope ratios g) elevated amounts of methylated nucleotides h) higher concentrations of plasma microproteins and mucopolysacharides i) greater need of exogenous zinc and j) high biowater content.
Many of the gross causes of cancer, such as dietary, environmental, occupational exposure to certain chemical substances or forms of electromagnetic radiation, have been elucidated through epidemiological studies. It is imperative, therefore, that they be identified and eliminated from the environment in so far as that is possible in modem industrial societies. In the annals of therapy, a quest to conquer, the impasse of cancer has been always fascinated by and large all disciplines of scientific community, especially natural product chemists. In 19th and 20th century, lot of research work has been carried out to find out the driving force behind this dreadful disease as well as large number of drugs have been introduced to counter its menace.
It is worthwhile at this juncture to look briefly at a few most powerful chemotherapeutic agents, which have been of paramount importance to the mankind and also to the researchers who have been actively involved in the synthesis and isolation of anticancer drugs. Lignans have been isolated from a number of plants (Achenbach, H., Waibel, R. and Meusah, I. Phytochemistry, 22 (3), 749-753 (1983); Nishibe, S., Hisada, S. and Inagaki, I. Phytochemistry, 10, 2231-2232 (1971); Barrero, A. F., Haidour, A. and Dorado, M. M. J. Nat. Prod. 42,159-162(1979)).
Recent studies on the biological activities of lignans prove beyond doubt the efficacy of these phytochemicals as cytotoxic agents (Macrae, W. D. and Towers, G. H. N. Phytochemistry 23 (6), 1207-1220 (1984)). Also recently lignans have been isolated from human urine and blood. This fact also suggests that lignans are playing a definite role in human physiology.
With the above background, the applicants have focussed their attention towards the identification and isolation of potent cytotoxic agents from plants. Literature data suggests the presence secoisolariciresinol in Cedrus deodara (Agarwal, P. K. and Rastogi, R. P. Phytochemistry, 21 (6), 1459-1461 (1982)) which is in all likelihood may be an artefact, is a proven antioxidant. Further investigation on Cedrus Deodara carried out by us led us to the isolation of a new lignan mixture comprising essentially (−)-Matairesinol, (−)-Wikshtronol and Dibenzyl butyrolactol in an extremely significant yield, Cedrus deodara is also a new source for these lignans. (−)-Wikstromol was first reported from wikstroemia viridiflora (Nishibe, S., Hisada, S. and Inagaki, I. Phytochemistry, 10, 2231-2232 (1971)). Matairesinol was isolated from a number of sources before (Nishibe, S., Hisada, S. and Inagaki, I. Phytochemistry, 10, 2231-2232 (1971); Tandon, S. and Rastogi, R. P. Phytochemistry, 15, 1789-1791 (1976)). The isolation of the dibenzylbutyrolactol [4,4′,9-trihydroxy-3,3′-dimethoxy-9,9′-epoxy lignan] was reported only once previously from the wood of Abies pinsapo (Barrero, A. F., Haidour, A. and Dorado, M. M. J. Nat. Prod. 42, 159-162 (1979)).
Keeping in mind the high yields of the lignans from Cedrus deodara and also the excellent biological activities and lignans in general (Macrae, W. D. and Towers, G. H. N. Phytochemistry 23(6), 1207-1220 (1984).